1. Definition of Inspection and Functional Verification
Inspection and Functional Verification is the quality-assurance discipline concerned with confirming that a machine or assembly has been correctly manufactured and assembled in accordance with drawings, specifications, quality standards, and safety requirements, and with verifying that it performs the required functions and achieves the required performance under actual operating conditions.
Inspection primarily confirms:
Dimensions
Geometry
Appearance
Assembly condition
Wiring condition
Piping condition
Component specifications
Fastening condition
Document conformity
Functional Verification confirms:
Whether the machine operates in the intended sequence
Whether sensors and actuators correspond correctly
Whether position, speed, pressure, and temperature are within the required range
Whether safety functions operate correctly
Whether faults and abnormal conditions are detected correctly
Whether performance remains stable during repeated operation
The core purpose of this discipline is:
To demonstrate with objective evidence that the machine is not only complete according to drawings, but also achieves the required function and performance in actual operation.
2. Purpose of Inspection and Functional Verification
The purpose of Inspection and Functional Verification is not simply to find defects.
It also serves to:
Confirm design intent
Confirm manufacturing quality
Detect assembly errors
Confirm safety
Verify functional completeness
Confirm performance level
Determine readiness for shipment
Prepare for customer acceptance
Establish maintenance references
Preserve quality history
Inspection is both an activity for detecting quality problems and an approval process for determining whether the product may proceed to the next stage.
3. Distinction Between Inspection, Verification, and Validation
Inspection
Inspection confirms whether a product or assembly conforms to specified requirements.
Main inspection targets include:
Dimensions
Geometry
Appearance
Assembly condition
Component specifications
Labels
Wiring
Piping
Verification
Verification confirms whether the design output satisfies the defined requirements.
Typical questions include:
Was it manufactured according to the drawings?
Were the specification requirements implemented?
Was the safety circuit constructed according to the design?
Validation
Validation confirms whether the system performs the intended function under actual operating conditions and in the intended environment.
Typical questions include:
Does it process the actual product reliably?
Does it meet productivity requirements at the installation site?
Can the operator use it safely and conveniently?
4. Basic Structure of the Inspection System
An inspection system is generally organized into the following stages:
Incoming inspection
Machining inspection
Subassembly inspection
In-process inspection
Final assembly inspection
Static functional inspection
Dynamic functional inspection
Safety-function inspection
Performance verification
Pre-shipment inspection
Site acceptance inspection
The scope and responsibility of each stage should be clearly defined.
5. Inspection Plan
An inspection plan defines what will be inspected, when it will be inspected, how it will be inspected, and who will perform the inspection.
Main items include:
Inspection target
Inspection stage
Inspection characteristic
Measurement method
Measuring instrument
Sampling method
Acceptance criteria
Judgment method
Recording method
Approval authority
The inspection plan should be prepared from the design-review stage.
6. Critical Characteristics
Not all characteristics need to be inspected at the same level.
Items that have a major influence on function or safety may be designated as Critical Characteristics.
Examples include:
Spindle runout
Linear-guide parallelism
Ball-screw alignment
Safety-circuit response
Pressure-vessel leakage
Electrical insulation
Emergency stop
Product-positioning accuracy
Fastening torque
Upper temperature limit
Critical characteristics require stricter inspection and more complete records.
7. Sources of Inspection Criteria
Inspection criteria are derived from documents such as:
Design drawings
Part drawings
Assembly drawings
Specifications
Customer requirements
Quality plans
Inspection standards
Safety requirements
Purchase specifications
Manufacturer manuals
Test procedures
It should be confirmed that criteria from different documents do not conflict.
8. Incoming Inspection
Incoming inspection confirms that externally supplied parts and materials conform to the required specifications.
Inspection items include:
Quantity
Model number
Material
Dimensions
Appearance
Surface treatment
Certificates
Inspection reports
Voltage
Pressure rating
Port specification
If an error is not detected during incoming inspection, significantly more rework may be required later in the assembly process.
9. Supplier Document Review
The following documents may be reviewed for purchased and subcontracted parts:
Material certificates
Heat-treatment certificates
Plating certificates
Welding records
Inspection reports
Calibration certificates
Certification documents
Shipment-inspection sheets
The existence of documents does not automatically guarantee actual product quality, so physical inspection should be performed where necessary.
10. Visual Inspection
Visual inspection detects abnormalities that can be identified by observation.
Inspection items include:
Scratches
Dents
Cracks
Deformation
Rust
Contamination
Paint defects
Plating defects
Damaged labels
Incorrect orientation
Missing parts
Visual inspection should distinguish cosmetic issues that do not affect function from damage that directly affects performance.
11. Dimensional Inspection
Dimensional inspection confirms whether the size and position of parts and assemblies are within specified tolerances.
Main items include:
Length
Width
Height
Diameter
Hole spacing
Depth
Center distance
Distance from datum surfaces
Assembly height
Typical measuring instruments include:
Vernier caliper
Micrometer
Height gauge
Bore gauge
Depth gauge
Coordinate measuring machine
Laser measuring instrument
12. Geometric and Form Inspection
Geometric inspection confirms the geometric condition of a part.
Inspection characteristics include:
Flatness
Straightness
Parallelism
Perpendicularity
Concentricity
Cylindricity
Circular runout
Total runout
Position
Geometric tolerances should be inspected in relation to functional datums.
13. Assembly-Dimension Inspection
Even when individual part dimensions are acceptable, the assembled dimensions may differ.
Assembly-dimension inspection may include:
Distance between modules
Shaft center height
Guide spacing
Sensor position
Product reference position
Cover clearance
Actuator stroke
Working height
It is important to confirm dimensions at the final functional point.
14. Datums and Measurement Coordinate Systems
Inspection results should be measured from clearly defined references.
Required references may include:
Master Datum
Datum surface
Datum axis
Origin
Machine coordinate system
Product coordinate system
If the inspection reference differs from the assembly reference, interpretation of the results may become difficult.
15. Measuring-Instrument Control
Measuring instruments used for inspection should be properly controlled.
Control items include:
Calibration status
Calibration interval
Measuring range
Resolution
Accuracy
Environmental conditions
Storage condition
Pre-use check
An instrument with expired calibration should not be used for official inspection.
16. Measurement System Analysis
The reliability of the measurement system itself should be evaluated.
Review items include:
Repeatability
Reproducibility
Bias
Linearity
Stability
Measurement uncertainty
If results vary significantly between operators or instruments when measuring the same part, the inspection system should be improved.
17. Sampling Inspection and 100% Inspection
The inspection scope should be determined according to importance and production type.
100% Inspection
Typical applications include:
Safety functions
Critical fastening
Custom-built one-off machinery
Leakage testing
Electrical insulation
Emergency-stop function
Sampling Inspection
Typical applications include:
Repetitive production parts
Stable suppliers
Noncritical visual characteristics
Mass-produced items
High-risk characteristics are generally more suitable for 100% inspection than sampling.
18. In-Process Inspection
In-process inspection prevents defects from passing into the next process.
Inspection items include:
Datum-surface condition
Assembly orientation
Positioning
Tightening torque
Preload
Wire numbering
Tube numbering
Lubrication condition
Alignment values
Intermediate dimensions
19. Hold Points and Witness Points
Hold Point
A Hold Point is an inspection stage beyond which work cannot proceed without approval.
Examples include:
Completion of frame alignment
Completion of linear-guide alignment
Safety-circuit inspection
Pressure test
Final inspection before power-up
Witness Point
A Witness Point is an inspection stage that may be observed by the designated party, but may proceed under defined conditions even if that party is not present.
20. Assembly-Condition Inspection
Before and after final assembly, the following should be confirmed:
Missing parts
Incorrect parts
Installation orientation
Assembly sequence
Interference
Cover condition
Guard condition
Adjustment mechanisms
Cable securing
Tube securing
21. Fastening Inspection
Fastened joints should be inspected for:
Bolt specification
Bolt length
Presence of washers
Tightening torque
Tightening sequence
Loosening prevention
Completion marking
Thread damage
Protrusion length
Critical joints may require torque records and tool identification.
22. Weld Inspection
Welds should be inspected for structural integrity.
Inspection items include:
Weld length
Weld size
Bead shape
Undercut
Overlap
Porosity
Cracks
Distortion
Missing welds
Where necessary, the following nondestructive tests may be used:
Liquid penetrant testing
Magnetic-particle testing
Ultrasonic testing
Radiographic testing
23. Adhesive and Sealing Inspection
Adhesive and sealing joints should be inspected for:
Surface preparation
Adhesive type
Applied quantity
Coverage area
Curing time
Curing temperature
Joint gap
Missing application
Bubbles
Leakage
Internal bond quality cannot always be fully determined by visual inspection alone.
24. Press-Fit Inspection
Press-fit joints should be inspected for:
Pressing direction
Pressing depth
Final position
Pressing force
Displacement
Cracks
Tilting
Rotational resistance
Pullout force
A servo press may record the force-displacement curve.
25. Precision-Assembly Inspection
Precision machine assembly should be inspected for:
Level
Straightness
Parallelism
Perpendicularity
Concentricity
Shaft runout
Backlash
Preload
Motion resistance
Repeatability
Measurements should be repeated after final tightening.
26. Linear-Guide Inspection
Linear-guide inspection should include:
Straightness of the reference rail
Parallelism of the secondary rail
Height difference between rails
Tightening torque
Block movement
Motion resistance
Local binding
Lubrication condition
27. Ball-Screw Inspection
Ball-screw inspection should include:
Parallelism with the guide system
Alignment of the fixed side
Alignment of the support side
Nut-housing position
Axial play
Rotational torque
Coupling alignment
Noise
Heat generation
28. Bearing and Spindle Inspection
Main inspection items include:
Bearing orientation
Fit
Preload
Lubrication
Axial position
Rotational torque
Radial runout
Axial runout
Temperature rise
Vibration
29. Electrical Inspection
Electrical inspection should confirm:
Incorrect wiring
Reverse polarity
Short circuit
Open circuit
Grounding
Terminal tightening
Crimp quality
Labeling
Cable damage
Shielding
30. Point-to-Point Test
A Point-to-Point Test confirms the starting and ending points of each electrical connection.
Inspection items include:
Continuity
Short circuit
Ground fault
Wire number
Terminal number
Connector pin
I/O address
Both ends of each cable
31. Insulation and Grounding Inspection
Electrical safety inspection may include:
Insulation resistance
Protective-earth continuity
Leakage current
Dielectric withstand
Polarity
Phase sequence
Test conditions should be defined according to product specifications and applicable standards.
32. Control-Panel Inspection
Control-panel inspection should include:
Device arrangement
Wiring ducts
DIN rails
Terminal blocks
Grounding bars
Fans
Filters
Device spacing
Labels
Door grounding
Spare space
33. Pneumatic Inspection
Pneumatic assembly should be inspected for:
Tube routing
Valve ports
Regulator settings
Pressure gauges
Flow-control valve direction
Fitting tightness
Residual-pressure release
Kinked tubing
Exhaust
Labels
34. Leakage Inspection
Leakage inspection may be applied to pneumatic, vacuum, and fluid systems.
Methods include:
Pressure-hold test
Flow-loss measurement
Soap-bubble inspection
Ultrasonic inspection
Helium leak testing
Vacuum-hold test
The allowable leakage rate and test duration should be clearly defined.
35. I/O Check
An I/O Check confirms that sensors and actuators correspond correctly to the programmed addresses.
Input Check
Sensor operation
Address
Logic
Polarity
Detection position
Output Check
Valves
Relays
Indicator lamps
Motors
Heaters
Buzzers
36. Basic Structure of Functional Verification
Functional verification generally proceeds in the following order:
Confirm static condition
Apply power
Confirm communication
Confirm I/O
Test individual actuators
Test manual operation
Test automatic sequence
Test safety functions
Test abnormal conditions
Test repeated operation
Verify performance
Final approval
37. Inspection Before Power-Up
Before applying power, confirm:
Main supply voltage
Phase sequence
DC polarity
Circuit-breaker rating
Short circuit
Grounding
Drive wiring
Valve-coil voltage
Emergency-stop condition
Mechanical interference in moving parts
38. Step-by-Step Power-Up
Power should be applied in stages for safety.
Example:
Confirm main power.
Apply control power.
Start the PLC.
Check the HMI.
Confirm communication.
Apply I/O power.
Apply drive power.
Supply compressed air.
Test actuators.
39. Manual-Operation Functional Verification
During manual operation, each actuator should be tested individually.
Inspection items include:
Direction of motion
Speed
Stroke
Sensor position
Interference
Motor rotation direction
Cylinder cushioning
Home position
Limit position
Stop function
40. Automatic-Operation Functional Verification
During automatic operation, the complete operating sequence should be verified.
Inspection items include:
Start conditions
Product detection
Clamping
Movement
Process operation
Completion signal
Discharge
Repetitive operation
Stop conditions
Timeout
41. Sequence Verification
Sequence verification confirms the logical connection between each operating step.
Review items include:
Previous-step completion condition
Next-step entry condition
Parallel actions
Mutual exclusion
Operating time
Timeout
Interruption condition
Restart condition
42. Interlock Verification
Interlocks prevent hazardous or impossible operations.
Verification examples include:
Automatic operation prohibited when a door is open
Axis movement prohibited until clamping is complete
Cylinder operation prohibited when pressure is insufficient
Process start prohibited when no product is detected
Automatic operation prohibited before homing
Drive operation prohibited when a cover is not installed
43. Safety-Function Verification
Safety functions should be verified separately from normal control.
Inspection items include:
Emergency stop
Door interlock
Light curtain
Safety mat
Safety relay
Safety PLC
Safe Torque Off
Contactor feedback
Prevention of restart
44. Emergency-Stop Verification
Emergency-stop testing should confirm:
Operation of all emergency-stop buttons
Stopping of hazardous motion
Power isolation
Treatment of residual pneumatic pressure
Safety of gravity-loaded axes
Required reset
Prevention of automatic restart
Warning indication
45. Fault Simulation
Abnormal conditions may be intentionally created to verify system response.
Examples include:
Sensor disconnection
Pressure reduction
Communication loss
Motor alarm
Overtemperature
Product jam
Door opening
Momentary power interruption
Emergency stop
Home-sensor fault
46. Alarm Verification
An alarm should not merely indicate an abnormal condition; it should also provide information about the cause and recovery method.
Inspection items include:
Alarm trigger condition
Alarm number
Alarm message
Fault location
Current state
Recovery method
Reset condition
Event logging
47. Recovery-Operation Verification
The machine should be verified for safe recovery after interruption.
Review items include:
Interruption position
Product condition
Axis position
Clamp condition
Residual energy
Manual recovery
Automatic recovery
Restart condition
Prevention of duplicate processing
48. Positioning-Accuracy Verification
Position-controlled machines should be verified for:
Absolute positioning accuracy
Repeatability
Reversal error
Backlash
Overshoot
Settling stability
Long-travel error
Position-dependent deviation
Where necessary, a laser interferometer, encoder, or external measuring instrument may be used.
49. Speed and Acceleration Verification
Motion axes should be verified for:
Maximum speed
Constant speed
Acceleration time
Deceleration time
Speed variation
Stopping distance
Vibration
Motor load
50. Pressure and Flow Verification
Pneumatic, hydraulic, and fluid systems should be verified for:
Supply pressure
Operating pressure
Pressure fluctuation
Minimum pressure
Maximum pressure
Flow rate
Response time
Pressure drop
51. Temperature-Function Verification
Heating and cooling systems should be verified for:
Target temperature
Rise time
Cool-down time
Overshoot
Temperature uniformity
Control stability
Sensor accuracy
Overtemperature protection
Thermal displacement
52. Force and Torque Verification
Pressing, clamping, fastening, and drive functions may require force and torque verification.
Inspection items include:
Maximum force
Minimum force
Holding force
Clamping force
Pressing force
Drive torque
Tightening torque
Overload protection
53. Vibration and Noise Verification
Vibration and noise during operation indicate assembly condition and machine performance.
Inspection items include:
Overall vibration level
Specific frequencies
Resonance
Bearing vibration
Motor vibration
Structural vibration
Noise level
Abnormal sound
54. Thermal-Stability Verification
Long-duration operation should confirm whether machine accuracy and performance remain stable.
Inspection items include:
Motor temperature
Bearing temperature
Control-panel temperature
Frame temperature
Position drift
Thermal displacement
Change in repeatability
Warm-up time
55. Repeated-Operation Test
Repeated-operation testing confirms functional stability and intermittent faults.
Review items include:
Number of cycles
Continuous operating time
Number of stops
Restart behavior
Sensor repeatability
Missing product detection
Temperature rise
Alarm occurrence
Position change
56. Endurance Test
An Endurance Test confirms durability and stability during long-duration operation.
Typical test targets include:
Bearings
Guides
Cylinders
Valves
Motors
Cable carriers
Sensors
Vacuum pads
Fastened joints
Test conditions may include:
Speed
Load
Number of cycles
Temperature
Pressure
Operating duration
57. Productivity Verification
Production equipment should meet the required production capacity.
Inspection items include:
Cycle time
Throughput
Equipment utilization
Product changeover time
Downtime
Rework rate
Defect rate
Bottleneck process
58. Product-Quality Verification
Machine function should also be verified through the quality of the final product.
Inspection items include:
Product dimensions
Appearance
Position accuracy
Assembly strength
Leakage
Machining quality
Repeatability
Process capability
59. Actual Product and Dummy Product
Functional verification may use an actual product or a test Dummy Product.
Dummy Product
Advantages include:
Safety
Reusability
Sensor adjustment
Initial testing
Actual Product
Purposes include:
Final functional confirmation
Actual process validation
Product-quality confirmation
Customer acceptance
60. Boundary-Condition Verification
Functions should be verified not only under normal conditions, but also at boundary conditions.
Examples include:
Minimum product size
Maximum product size
Minimum pressure
Maximum pressure
Low temperature
High temperature
Low speed
High speed
Minimum load
Maximum load
61. Worst-Case Test
A Worst-Case Test confirms whether function is maintained under the most unfavorable conditions.
Example combinations include:
Maximum load and maximum speed
Minimum pressure and maximum friction
High temperature and long-duration operation
Minimum voltage and maximum load
Limit-tolerance product and repeated operation
62. Software and Parameter Verification
Control software and parameter settings are also subject to verification.
Inspection items include:
PLC program version
HMI version
Servo parameters
Inverter parameters
Network addresses
Recipes
User authority levels
Backups
Recovery files
63. User-Interface Verification
The HMI and operator devices should be easy to understand and use.
Inspection items include:
Screen layout
Button operation
Status display
Alarm display
Language
Units
Operating authority
Prevention of incorrect input
Screen transitions
Data recording
64. Maintenance-Function Verification
It should be confirmed that the machine can be maintained as intended.
Inspection items include:
Accessibility
Cover removal
Component replacement
Cable disconnection
Tube disconnection
Lubrication
Filter replacement
Sensor adjustment
Restoration of reference position
Reassembly
65. Guard and Cover Verification
Guards and covers should prevent access to hazardous areas.
Inspection items include:
Fixing condition
Gaps
Openings
Interlocks
Rigidity
Visibility
Required removal tools
Maintenance access
Warning labels
66. Human-Factors Verification
Operator usability and safety may also be included in functional verification.
Review items include:
Working height
Reach distance
Visibility
Operating force
Working posture
Product loading
Product unloading
Warning recognition
Emergency-stop accessibility
Maintenance posture
67. Inspection Result Judgment
Inspection results should be judged according to clearly defined criteria.
Typical judgment categories include:
Accept
Conditional acceptance
Rework
Repair
Concession acceptance
Scrap
Reinspection
Judgment authority and approval procedures should be defined.
68. Nonconformance Control
When a nonconformance is found, the following should be recorded:
Location of nonconformance
Description of nonconformance
Required criterion
Actual measured value
Process where detected
Cause
Temporary action
Final corrective action
Reinspection result
69. Rework and Reinspection
After rework, all affected characteristics should be reinspected.
Examples include:
Recheck parallelism after guide realignment
Repeat Point-to-Point Test after wiring correction
Repeat visual and nondestructive inspection after weld repair
Recheck position and pullout force after press-fit rework
Repeat functional test after program modification
70. Root Cause Analysis
Repeated defects require root-cause analysis.
Areas to investigate include:
Design
Part tolerances
Assembly sequence
Work instructions
Measurement methods
Tools
Environment
Operator training
Suppliers
Software
71. Inspection Records
Inspection records may include:
Machine number
Part number
Assembly number
Inspection date
Inspector
Measuring instrument
Calibration number
Measured value
Allowable value
Judgment
Remarks
Approver
72. Functional-Verification Records
Functional-verification records should include:
Test item
Test condition
Input state
Output result
Measured value
Expected result
Actual result
Judgment
Alarm
Recovery result
73. Traceability
Traceability allows related parts and processes to be identified when a problem occurs.
Traceability items include:
Part lot
Serial number
Operator
Tool
Program version
Parameters
Inspection results
Rework history
Shipment date
Customer installation information
74. FAT
Factory Acceptance Test is an acceptance test conducted at the manufacturing facility before shipment.
Main items include:
Appearance
Dimensions
Function
Safety
Sequence
Productivity
Product quality
Documentation
Options
Customer requirements
75. SAT
Site Acceptance Test is an acceptance test conducted after installation at the customer site.
Main items include:
Installation condition
Electrical power
Pneumatic supply
Communication
Level
Site interfaces
Actual product
Production conditions
Safety
Training
76. Difference Between FAT and SAT
Category | FAT | SAT |
|---|---|---|
Location | Manufacturing facility | Customer site |
Purpose | Confirm completeness before shipment | Confirm operability after installation |
Conditions | Controlled test environment | Actual installation environment |
Product | Dummy or sample product | Actual product |
Interfaces | May be partially simulated | Connected to actual equipment |
Result | Shipment approval | Final acceptance |
77. Pre-Shipment Inspection
Before shipment, confirm:
Functional testing completed
Safety inspection completed
Alarms resolved
Fastening marks applied
Lubrication completed
Moving parts secured
Protective packaging
Accessories
Spare parts
Documentation
Program backup
78. Verification Before Transportation
The machine should be checked to prevent damage during transportation.
Inspection items include:
Securing of moving parts
Axis brakes
Protection of precision parts
Cable securing
Tube protection
Sensor protection
Rust prevention
Moisture protection
Center of gravity
Lifting points
9. Reinspection After Site Installation
After site installation, the following should be reconfirmed:
Base level
Frame deformation
Axis alignment
Supply voltage
Grounding
Pneumatic pressure
Communication
Safety circuits
Positioning accuracy
Functional sequence
80. Customer-Acceptance Documentation
The following documents may be provided during customer acceptance:
FAT Report
SAT Report
Inspection report
Electrical schematic
Pneumatic circuit diagram
I/O List
Manual
Parts list
Spare-parts list
Program backup
Calibration records
Maintenance plan
81. Major Design and Quality Deliverables
Deliverable | Purpose |
|---|---|
Inspection Plan | Defines the overall inspection plan |
Quality Control Plan | Defines quality-control items for each process |
Incoming Inspection Standard | Defines incoming-inspection criteria |
In-Process Inspection Sheet | Records in-process inspection results |
Final Inspection Checklist | Defines final assembly inspection criteria |
Functional Verification Plan | Defines functional-verification scope and methods |
Safety Validation Plan | Defines safety-function verification methods |
I/O Check Sheet | Records input and output verification results |
Leak Test Procedure | Defines leakage-test conditions and acceptance criteria |
Performance Test Plan | Defines performance-verification items |
Endurance Test Plan | Defines endurance-test conditions |
FAT Protocol | Defines the Factory Acceptance Test procedure |
SAT Protocol | Defines the Site Acceptance Test procedure |
Nonconformance Report | Records nonconformance and corrective action |
Final Acceptance Report | Records final approval results |
82. Inspection Review Questions
Are the inspection criteria clear?
Are critical characteristics identified?
Is the inspection timing appropriate?
Are the measuring instruments suitable for the tolerances?
Is calibration status valid?
Does the measurement datum match the assembly datum?
Are in-process Hold Points defined?
Are inspection results recorded?
Is there a nonconformance-control procedure?
Is reinspection after rework defined?
83. Functional Verification Review Questions
Does manual operation function correctly?
Does the automatic sequence operate as required?
Do interlocks prevent hazardous actions?
Does the emergency stop safely stop all hazards?
Are alarm and recovery procedures clear?
Are abnormal conditions detected correctly?
Do position, speed, pressure, and temperature meet the required values?
Is performance stable during repeated operation?
Has the function been confirmed using the actual product?
Have boundary conditions and Worst-Case conditions been tested?
84. Main Causes of Inspection and Verification Failure
Unclear requirements
Missing inspection criteria
Unsuitable measuring instruments
Incorrect measurement methods
Operator variation
Environmental effects
Assembly errors
Program errors
Missing interlocks
Insufficient test conditions
Missing records
Failure to reinspect after rework
85. Conclusion
Inspection and Functional Verification is not merely the final process for checking a completed machine.
It is a quality-assurance system that objectively demonstrates design intent, manufacturing quality, assembly condition, safety functions, and actual operating performance.
The key is to manage the following relationships consistently:
Requirements and inspection criteria
Design drawings and actual assembly
Part accuracy and final function
Measured values and measurement uncertainty
In-process inspection and final inspection
Static inspection and dynamic verification
Normal conditions and abnormal conditions
Safety circuits and actual hazards
Program logic and actual operation
Factory testing and site acceptance
Nonconformance and reinspection
Test results and traceability information
A good inspection system is not one that simply finds many defects.
It is a system that detects incorrect conditions before they create larger problems, demonstrates critical functions and safety with objective data, and allows repeated judgment using consistent criteria.
Through this approach, inspection and functional verification become not a final pre-shipment check, but a standardized quality-assurance process connected to design, assembly, commissioning, acceptance, and maintenance.